Smelting and refining of iron, steel, and other metals in open-hearth furnaces



1,618,934 P. KUHN AND OTHER METALS IN Feb. 22 1927.

SMELTING AND REFINING OF IRON, STEEL,

OPEN HEARTH FURNACES Filed May 5 1926 Fig.2

gylearrzey Patented l 'eb. 22,1927.

UNITED STATES 1,618,934 PATENT OFFICE.

PAUL xumr, or nmnnnscnELnnN-on-rnE-smc, GERMANY.

SMELTING AND BEFINING OF IRON,

STEEL, AND b'rnnn METALS IN OPEN-HEARTS summons.

Application filed May 3, .1926, Serial No. 106,457, and in Germany February 23, 1925.

This'invention relates to improvements in open hearth furnaces for the smelting and refining of'iron, steel and other metals.

Very costly apparatus is required in treating steel and other metals in furnaces of the Siemens-Martin type.. The construction of the latterfurnaces is very complicated and comprises a number of regenerative and slag considerable damage to the refractory bricks..-

The Martin furnace is used mainly for smelting and making Siemens-Martin steel and only to a slight extent for refining steel, since the high temperature required for refining has a destructive effect upon the fur-f nace and more particularly upon the endof the furnace at which the gases, are withdrawn. a In electric furnaces the charge can be melted and, because of the particular con,.- The installation costs are considerably 'less than for the usual'forms of furnace.

'struction of and the high temperature obtained in such furnaces, the charge can be refined therein. However, electric furnaces are not economical, mainly on account of the high cost of the current and in consequence such furnaces are adapted only for the production of high grade steels.

According to the present invention the hearth is similar to that of an electric furnace, with the difference, however, that the fuel is introduced into the hearth almost vertically through the arch of the roof.

Chambers are directl connected to each end of the hearth cham ers and are so constructed that the liquid slag formed in the checker work flows back to the hearth. The

narrow flame, which has t e same effect as f the voltaic arc of the electric furnace. This hot flame bears directly on the charge which is quickly melted." The bath can then be Irefined in exactly the same manner as in the electric furnace.

The waste ases traverse the hearth and, already cooled to some extent, enternthe adair for combustion is heated by passage joining chambers, and, after passing through these and'the valves, are led to the chimney.

The construction of the furnace with the chambers directly adjoining the hearth is such that the waste gases have a long path to traverse, so that they are almost completely cooled; in these chambers. The air for combustion traverses the chambers in the opposite direction and is highly heated thereby so that substantially all-of the heat given up by the waste gases is returned to the'furnace.

The apparatus is particularly adapted for use with rich gases, such as distillation, lighting and coke oven gases, all tar and 1 mineral oils, tar, pulverized coal, mixtures of poor gases with .pulverized fuel, distillation and lighting gas and the like.

The invention hasthe following advantages over the Siemens-Martin furnaces in use up to the present time High grade steels can be produced by the "furnace of this invention- 2." An rich and gaseous fuel may be used.

4. By the practically complete recovery of the heat of the waste gases the fuel consumption is considerably less than in furnaces commonly used.

5. The whole process is consequently carried out at less cost than those in present use.

In the accompanying drawing which shows. a furnace constructed according-to 90, the invention,

Fig. '1 is a vertical section of a furnace embodying the invention.

, Fig. 2 is a horizontal section of the same.

Chambers a are arranged on each sideof the hearth and other chambers 72, c, d are connected to the chambers a.

The air for combustion is led alternately to and from the chambers and similarly the heated waste gases are led from the hearth alternately to and from thechambers in the, opposite direction to the air. The burners are disposed over the hearth adjacent the outlets of the chambers a. Checker work is contained in each ofthe chambers a, b, 0 and d and occupies the entire space between the floors and the roofs of said chambers. The floors of the chambers a slopeforward to the hearth in order to return any slag formed in said chambers;

I claim: directly communicating with said first- An open hearth re enerative furnace for named chambers and also containing regenthe smelting and re ning of metals, comerative checker work, thereby forming a 15 prising a hearth, chambers on both sides of path of maximum length for the passage'of 5 the hearth containing regenerative checker the waste gases and resulting in complete work, saidv chambers and checker work being cooling of the latter, said chambers being immediately contiguous to the hearth and adapted. for alternate connection with the communicating directly therewith, the air supply and with the waste gases. 2 checker work occupying the entire space be- In testimony whereof I have hereunto set 10 tween the floors and roofs of said chambers, my. hand.

the floors of said chambers sloping into said hearth, additional chambers adjoming and 7 PAUL 

